1998 GMC Sonoma Owner's Manual - Page 18

But don't have a seatback reclined if your vehicle is moving. Sitting in a reclined position when your vehicle is in motion can be dangerous. Even if you buckle up, your safety beltscan't do their job when you're reclined like this. The shoulder belt can't do its job because it won't beagainst your body. Instead, it will be in front of you. In a crash you could go into it, receiving neckor other injuries. The lap belt can't do its job either. In a crash the belt could go up over your abdomen. The belt forces would be there, at your pelvic bones. not This could cause serious internal injuries. For proper protection when the vehicle is in motion, havethe seatback upright. Then sit well back in the seat and wear your safety belt properly. 1-4